fix[ux]: fix error message for "staticall" typo (#4438)

the "staticall" typo is very common, and was raising a hard-to-read
error message from the python parser like "invalid syntax. Perhaps you
forgot a comma?"

this commit adds logic to `ast/parse.py`, so we can add a hint to the
exception after we have successfully gone through the python parser and
have the ability to add source info and a hint.

tests/functional/syntax/exceptions/test_syntax_exception.py

@@ -1,5 +1,6 @@
 import pytest
 
+from vyper.compiler import compile_code
 from vyper.exceptions import SyntaxException
 
 fail_list = [
@@ -107,5 +108,30 @@ def foo():
 
 
 @pytest.mark.parametrize("bad_code", fail_list)
-def test_syntax_exception(assert_compile_failed, get_contract, bad_code):
-    assert_compile_failed(lambda: get_contract(bad_code), SyntaxException)
+def test_syntax_exception(bad_code):
+    with pytest.raises(SyntaxException):
+        compile_code(bad_code)
+
+
+def test_bad_staticcall_keyword():
+    bad_code = """
+from ethereum.ercs import IERC20Detailed
+
+def foo():
+    staticcall ERC20(msg.sender).transfer(msg.sender, staticall IERC20Detailed(msg.sender).decimals())
+    """  # noqa
+    with pytest.raises(SyntaxException) as e:
+        compile_code(bad_code)
+
+    expected_error = """
+invalid syntax. Perhaps you forgot a comma? (<unknown>, line 5)
+
+  contract "<unknown>:5", line 5:54 
+       4 def foo():
+  ---> 5     staticcall ERC20(msg.sender).transfer(msg.sender, staticall IERC20Detailed(msg.sender).decimals())
+  -------------------------------------------------------------^
+       6
+
+  (hint: did you mean `staticcall`?)
+    """  # noqa
+    assert str(e.value) == expected_error.strip()

vyper/ast/parse.py

@@ -86,7 +86,16 @@ def _parse_to_ast_with_settings(
             # SyntaxError offset is 1-based, not 0-based (see:
             # https://docs.python.org/3/library/exceptions.html#SyntaxError.offset)
             offset -= 1
-        raise SyntaxException(str(e.msg), vyper_source, e.lineno, offset) from None
+        new_e = SyntaxException(str(e), vyper_source, e.lineno, offset)
+
+        likely_errors = ("staticall", "staticcal")
+        tmp = str(new_e)
+        for s in likely_errors:
+            if s in tmp:
+                new_e._hint = "did you mean `staticcall`?"
+                break
+
+        raise new_e from None
 
     # Add dummy function node to ensure local variables are treated as `AnnAssign`
     # instead of state variables (`VariableDecl`)

vyper/exceptions.py

@@ -192,15 +192,14 @@ class VyperException(_BaseVyperException):
 
 
 class SyntaxException(VyperException):
-
     """Invalid syntax."""
 
-    def __init__(self, message, source_code, lineno, col_offset):
+    def __init__(self, message, source_code, lineno, col_offset, hint=None):
         item = types.SimpleNamespace()  # TODO: Create an actual object for this
         item.lineno = lineno
         item.col_offset = col_offset
         item.full_source_code = source_code
-        super().__init__(message, item)
+        super().__init__(message, item, hint=hint)
 
 
 class DecimalOverrideException(VyperException):